The present invention relates to a rotary engine, especially it relates to improvements of a rotary engine that comprises a trochoid rotor housing and a rotor which is mounted on an eccentric shaft in the housing. More particularly, the invention relates to a side port intake type rotary engine wherein intention is made to equalize the blow-bye gas pressure in both side face spaces of the rotor between the side face of the rotor and the housing member thereof disposed in each of the sides of the rotor, that is, between the rotor and the side housing member and the intermediate housing member in both sides of the rotor (in the side face space of the rotor between the side seal and the oil seal).
That is, the present invention relates to a rotary engine in which the blow-bye gas pressure difference between both sides of the rotor is attenuated which blow-bye gas leaks into the inside of the side seal disposed in each side of the rotor.
The present invention also relates to improvements of a Wankel type rotary engine which is of a side intake port type in which intake gas is introduced through an intake port disposed independently in each side of the rotor. More particularly, the invention relates to improvements of an intake port portion of the center housing (intermediate housing) of the rotary engine which comprises an injector for electronically controlled fuel injection at the intake port portion to enhance the engine power.
The gas pressure difference between both sides of the rotor is resulted from the following structure of the rotary engine in accordance with the related art.
That is, both side seals covering the side faces of the rotor are not exactly the same in terms of dimension, profile and matching state with the sealing groove so that the introduction rate of the high temperature and high pressure combustion gas is different for each of the side faces of the rotor.
In accordance with the related art rotary engine comprising an electronically controlled fuel injection system using an injector, the intake port of the intermediate housing on which the injector is disposed is smaller than that of the side housing, therefore the end portions of the intake ports of the intermediate housing and the side housing are not aligned with each other.
Therefore, the opening ends of the two intake ports of the two opposing housings are dislocated with respect to each other. More precisely, the opening end of the main intake port of the intermediate housing is located in the retard side with respect to that of the side housing.
As a result of such a misalignment of the intake ports disposed in both sides of the rotor, especially that of the opening ends thereof, the timing of connection between the intake port and the side face space of the rotor becomes different for each of the sides of the rotor, respectively, according to the rotation of the rotor.
Therefore, the timing of flowing the blow-bye gas which leaks through the side seal of the rotor into the inside thereof becomes different for each of the sides of the rotor. More precisely, with regard to the rotor side face space which in advance comes in contact with the intake port, the blow-bye gas passes through the space ahead so that the pressure in the space of this side is lowered while the other side space is still maintained at a high pressure since the space of the other side has not come in contact with the intake port yet.
Due to the above-mentioned pressure difference between the both sides of the rotor, the rotor is forced to shift to one of the sides thereof. Assuming that the pressure difference is 1 kg/cm.sup.2, the rotor is urged by a force of 70 kg/cm.sup.2 since the area of the side face of the rotor (the area of the blow-bye gas reservoir between the side seal and the oil seal) is usually 70 cm.sup.2. Due to this force, one of the sides of the rotor is pressed against the side housing whereas the side seal of the other side of the rotor is instantly separated from the other side housing.
Therefore, frictional resistance is generated between the rotor and the one of the side housings while the high pressure gas further leaks into the side face space of the other side of the rotor through the side seal so that the engine is excessively heated due to the leakage of the high temperature combustion gas. This causes loss of power and overheat of the engine.
It is to be noted that, in the related peripheral intake type rotary engine comprising an intake port disposed inside of the rotor housing trochoid surface, in order to equalize the blow-bye gas pressure in both sides of the rotor to cope with the above-mentioned problems, a gas pressure balance port is provided through the rotor to connect both sides thereof. However, the balance port is a simple hole penetrating through the rotor and the opening surface plane of the hole is the same as that of the rotor side surface. Therefore, the gap between the opening on the rotor side face and the sliding surface of the side housing (or intermediate housing) is very small (about 0.2 mm) and the passage space toward the balance port is very narrow so that flow resistance is large and flow rate is small. Therefore, the problems due to the pressure difference between both sides of the rotor are not obviated by the related balance port structure.
Actually, the engine provided with such a balance port is not commercialized.
In accordance with the related rotary engine provided with an electronically controlled fuel injection system using an injector, the diameter of the intake port disposed on the injector side is smaller than that of the intake port disposed on the side housing. Therefore, the location of the intake ports are not the same.
Accordingly, the opening end of the intake port of one of the sides of the rotor (inside of the side seal) is dislocated from that of the other side of the rotor.
For example, the misalignment of the opening ends of the intake ports is about 20 mm between the both sides of the rotor of a turbo rotary engine mounted on an automobile commercialized from Matsuda Co. limited. With regard to a nonturbo rotary engine commerciallized from the company, the misalignment is about 10 mm.
As a result of such a misalignment of the intake ports disposed in both sides of the rotor, especially that of the opening ends thereof, the timing of connection between the intake port and the side face space of the rotor becomes different for each of the sides of the rotor, respectively, according to the rotation of the rotor.
Therefore, the timing of flowing the blow-bye gas which leaks through the side seal of the rotor into the inside thereof becomes different for each of the sides of the rotor. More precisely, with regard to the rotor side face space which in advance comes in contact with the intake port, the blow-bye gas passes through the space ahead so that the pressure in the space of this side is lowered while the other side space is still maintained at a high pressure since the space of the other side has not come in contact with the intake port yet.
Due to the above-mentioned pressure difference between the both sides of the rotor, the rotor is forced to shift to one of the sides thereof. Due to this force, one of the sides of the rotor is pressed against the side housing whereas the side seal of the other side of the rotor is instantly separated from the other side housing.
Therefore, frictional resistance is generated between the rotor and the one of the side housings while the high pressure gas further leaks into the side face space of the other side of the rotor through the side seal so that the engine is excessively heated due to the leakage of the high temperature combustion gas. This causes loss of power and overheat of the engine.